- A fifth of Brits (19%) secretly change the thermostat behind their partner’s back[1], new research released ahead of Valentine’s Day reveals
- One million couples argue about thermostats every day[2], with 400,000 rowing daily about energy bills[3], and 786,000 fighting over heating costs[4]
- Meanwhile, one in six (16%) Gen Z couples turn up the heat on their relationships by raising the thermostat temperature for a romantic evening[1]
- Two-fifths of households (38%) regularly fall out over the cost of heating, with a total of nearly 619 million arguments each year[5]
- One in three households (35%) have fallen out about the cost of their energy bills[6], while two-fifths (44%) argue over leaving lights on in empty rooms[7]
- Uswitch.com urges households to avoid quarrels about the cost of energy by switching to a cheap fixed deal.
Is your relationship hotting up ahead of Valentine’s Day? Or is it just that your partner is among the fifth of Brits (19%) who admit to sneakily changing the thermostat temperature behind your back[1], according to new research by Uswitch.com, the comparison and switching service.
The thermostat can be a major flashpoint in relationships, with a third of couples who live together (36%) admitting to arguing over the temperature it’s set to. Partners typically argue about the thermostat once a fortnight, but more than one million couples argue about it every day[2].
Energy bills are another major source of conflict, with three in ten couples (31%) arguing about the amount they pay for gas and electricity – with 400,000 fighting every day about it[3]. Heating costs also spark fights among a third of couples (35%), with 786,000 rowing daily[4].
Thermostats can sometimes bring couples together, however, with one in six Gen Z couples (16%) admitting to turning up the temperature to enjoy a romantic evening[5].
Households most often argue about leaving appliances on standby, with one in three homes (37%) having 36 rows a year on average about the subject. The next most common battles are over leaving the TV on when no one is watching it, and leaving lights on in empty rooms, with both inspiring 34 arguments a year.
Two-fifths of households (38%) regularly fall out over the cost of heating, causing an incredible 235 million arguments each year[5]. One in three households (35%) have had a spat about the cost of their energy bills, and two-fifths (39%) have argued about how much they’re spending on heating[6].
Experts recommend heating your home to between 18°C and 21°C during winter. Turning your thermostat down by just one degree could reduce your energy bill by up to 10%, according to The Energy Saving Trust[7].
Table: Most common households arguments
| Issue | % households that argue about this | Average # of rows per year |
|---|---|---|
| Leaving lights on in empty rooms | 44% | 34 |
| Leaving the TV on with no one watching | 40% | 34 |
| Leaving gadgets on (TVs, gaming consoles, speakers) | 40% | 32 |
| Cost of heating | 39% | 22 |
| The temperature of the thermostat | 39% | 29 |
| Leaving doors open to the outside when it’s cold/cool | 38% | 28 |
| Putting the heating on instead of wearing a jumper | 37% | 29 |
| Keeping appliances on standby | 37% | 36 |
| Leaving windows open | 36% | 27 |
| Energy bills | 36% | 17 |
| Leaving the fridge door open | 34% | 26 |
| Boiling the kettle and forgetting about it | 34% | 27 |
| Too much time spent on games consoles | 31% | 32 |
| Cost of showers & baths | 30% | 18 |
| Running the washing machine when it isn’t full | 30% | 17 |
| Using the tumble dryer (instead of airing clothes) | 29% | 24 |
| Poorly stacking the dishwasher resulting in extra loads | 29% | 17 |
| Running the dishwasher when it isn’t full | 24% | 17 |
| Forgetting to submit a meter reading | 21% | 11 |
| Forgetting to charge the electric car | 17% | 29 |
Source: Uswitch.com
Although leaving the lights on causes plenty of arguments, it adds relatively little to bills. A 4.2W LED bulb left on for an extra four hours a day would add just £1.70 to bills over a year[8].
Parents claim they turn off 386 lights in empty rooms every year on average, although it might not be the children who are to blame, as adult children living with their parents say they switch off 536 a year[9]!
Uswitch.com is urging couples and households who are fighting over energy costs to reduce their bills by looking into the best deals available.
Households switching from a standard variable tariff to the cheapest fixed deal right now could save an average of £238 a year — with average costs around 15% cheaper than the current price cap[9].
Natalie Mathie, energy expert at Uswitch.com, comments: “If you’re getting the cold shoulder from your partner this Valentine’s Day, it might be because you’ve been tinkering with the thermostat temperature behind their back.
“A fifth of couples are guilty of this sneaky behaviour, and it’s one of the biggest causes of arguments between partners.
“Leaving the odd light on or occasionally forgetting to turn off the TV isn’t going to make a big difference to your bills, but there are good habits that will save us a significant sum of money over the course of the year.
“There’s one quick and easy way that you could save yourself hundreds of pounds a year on your energy bill.
“The cheapest fixed deal is currently £238 less than a standard variable tariff, which two-thirds of households are on. There are many other fixed rate tariffs with similar savings, making it a no-brainer to switch at a time when winter energy use is at its highest.
“If you haven’t fixed in a year or more, you’re probably on a standard tariff and paying more than you need to. Running a quick energy comparison using your postcode is the easiest way to see what’s available and lock in a cheaper rate.”
See if you can save by comparing energy deals at Uswitch.com
For more information
Rianna York | Energy PR Manager
rianna.york@rvu.co.uk
Twitter: @UswitchPR
Notes to editors
Research conducted online by Opinium, 23 to 27 January 2026 , among 2,000 UK residents, weighted to be nationally representative.
1. Respondents were asked ‘Which, if any, of the following statements are true to you about the heating in your home? I will sometimes change the thermostat behind my partner’s back.’ 19% of people with a partner said yes. Respondents were asked ‘Which, if any, of the following statements are true to you about the heating in your home? Me and my partner will sometimes turn up the thermostat for a romantic evening.’ 16% of Gen Z said yes.
2. Respondents were asked ‘How often does your household argue about each of the following things? The temperature of the thermostat.’ 44 people who live with their partner said ‘daily’. 44/2000 x 58.4 million = 1.28 million couples.
3. Respondents were asked ‘How often does your household argue about each of the following things? Energy bills.’ 14 people who live with their partner said ‘daily’. 14/2000 x 58.4 million = 408,800 couples.
4. Respondents were asked ‘How often does your household argue about each of the following things? Cost of heating.’ 27 people who live with their partner said ‘daily’. 27/2000 x 58.4 million = 788,400 couples.
5. Respondents were asked ‘How often does your household argue about each of the following things? Cost of heating.’ 58% replied Never. 4% said ‘N/A - this isn’t relevant to our household.’ 100% - 58% - 4% = 38% who do argue about it. Average yearly arguments = 21.8. 21.8 x 38% x 28.4 million households = 235 million arguments.
6. See table in release.
8. 4.2W bulb x £0.2769 x 1,456 hours = £1.71. Respondents were asked ‘How many times a week do you do the following things?’ including ‘turn off lights in empty rooms’. Weekly figure of 7.4 multiplied by 52 to get an annual figure of 386. Adult children who live with parents said 10.3 a week. 10.3 x 52 = 536.
10. Uswitch data.